Heat stress can have large effects on most aspects of reproductive function in mammals. These
include disruptions in spermatogenesis and oocyte development, oocyte maturation, early embryonic
development, foetal and placental growth and lactation. These deleterious effects of heat stress
are the result of either the hyperthermia associated with heat stress or the physiological adjustments
made by the heat-stressed animal to regulate body temperature. Many effects of elevated temperature
on gametes and the early embryo involve increased production of reactive oxygen species.
Genetic adaptation to heat stress is possible both with respect to regulation of body temperature
and cellular resistance to elevated temperature.